Identification of Amber and the Copal under Heat Pressurized Process

Abstract:

Amber and copal belong to the natural resin, which are similar and transitional in the physical and chemical properties. The artificial heat-pressurized treatment is contributed to the polymerization of the natural copal, and turns into green, yellow-green and deep orange-yellow copal. It is very difficult to identify amber from the heat- pressurized treatment copal only based on the gemological parameters.The thermal behavior of amber and the copal before and after heat-pressurized treatment were analyzed by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). The results show that amber exists an evident endothermic peak around 123~132°C, and copal reveals an obvious endothermic peak at about 174~178°C, and the heat pressurized treatment copal occurs a clear exothermic peak around 150~152°C. The differences between endothermic or exothermic transition and peak position reveal occurring thermal oxidation or the bond breaking or the melting, which are of great significance in the identification.

• Periodical: Advanced Materials Research (Volumes 554-556)
• Pages: 2112-2115
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.554-556.2112
• Online since: July 2012
• Authors: Hui Li, Xuan Wang, Yong Zhu, Qin Ren
• Keywords: AMBER, Copal, Heat Pressurized Treatment, Identify, Thermal Analysis

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